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Study on Cutting Force,Cutting Temperature and Machining Residual Stress in Precision Turning of Pure Iron with Different Grain Sizes

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Chinese Journal of Mechanical Engineering 2020年第4期33卷 159-167页

作者： Yinfei Yang lu jin jinpeng Zhu jinxing Kong Liang Li College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Pure iron is one of the difficult-to-machine materials due to its large chip deformation,adhesion,work-hardening,and built-up edges formation during *** leads to a large workpiece deformation and challenge to meet the required technical ***,under varying the grain size of pure iron,the influence of cutting speed,feed,and depth of cut on the cutting force,heat generation,and machining residual stresses were explored in the turning process to improve the machinability without compromising the mechanical properties of the *** experimental findings have depicted that the influence of grain size on cutting force in the precision turning process is not ***,the cutting temperature and residual stress of machining fine-grain iron were much smaller than the coarse grain at all levels of cutting parameters.

关键词： Pure iron Grain size Cutting parameter Cutting force Cutting temperature Residual stress

Residual Stress Relaxation of Thin‑walled Long Stringer Made of Aluminum Alloy 7050‑T7451 under Transportation Vibration

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Chinese Journal of Mechanical Engineering 2020年第3期33卷 150-159页

作者： Yinfei Yang lu jin Jixing Du Liang Li Wei Yang Nanjing University of Aeronautics and Astronautics Nanjing 210016China Shenyang Aircraft Corporation Shenyang 110034China.

Thin-walled long stringer made of aluminum alloy 7050-T7451 is prone to deformation during transportation,so a research of residual stress relaxation was launched in this *** transport resonance stress of long stringer was analyzed based on the power spectral density of road transport *** residual stress relaxation experiment of aluminum alloy 7050-T7451 under different equivalent stress levels was designed and carried *** to the amount of residual stress relaxation in the experiment,an analytical model was established with the equivalent stress level *** deflection range of long stringer was evaluated under different damping *** results show that when the equivalent stress exceeds 0.8σ0.2,the residual stress relaxation of the thin-walled samples *** residual stress relaxation increases linearly with the equivalent stress,which is logarithmically related to the loading *** deformation caused by residual stress relaxation of the long stringer is proportional to the square of the length and the bending moment caused by stress rebalance,and inversely proportional to the moment of inertia of the *** the damping ratio decreases from 0.03 to 0.01,the total deflection of the long stringer increases from 0 to above 1.55 mm.

关键词： Aluminum alloy 7050-T7451 Large thin-walled part Transportation process Residual stress Structural deformation

Identification of anti-cancer compounds from natural products

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Chinese Journal of Natural Medicines 2020年第7期18卷 481-482页

作者： lu jin-Jian WANG Yi-Tao State Key Laboratory of Quality Research in Chinese Medicine Institute of Chinese Medical SciencesUniversity of MacaoMacao 999078China

Natural products serve as abundant resources with diversity of chemical structures,which has been widely explored for the pharmacological researches and drug discovery[1,2].They are generally isolated from microorgani... 详细信息

关键词： cancer abundant compounds

Toxicity of perfluorononanoic acid and perfluorooctane sulfonate to Daphnia magna

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Water Science and Engineering 2015年第1期8卷 40-48页

作者： Guang-hua lu Jian-chao Liu Li-sha Sun lu-jin Yuan Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education College of Environment Hohai University

In order to study toxicological effects of perfluorononanoic acid （PFNA）, perfluorooctane sulfonate （PFOS）, and their mixtures （PFNA/ PFOS） on Daphnia magna （D. magna）, a suite of comprehensive toxicity tests were conducted, including a 48-h acute toxicity test, a 21-day chronic test, a feeding experiment, and a biomarker assay. D. magna were exposed to aqueous solutions of PFNA and PFOS （alone and in combination） at concentrations ranging from 0.008 to 5 mg/L. The survival, growth, and reproduction of D. magna were monitored over a 21- day life cycle. The biomarkers, including acetylcholinesterase （ACHE）, superoxide dismutase （SOD）, and catalase （CAT） activities, were determined after seven days of exposure. PFOS was more toxic than PFNA based on the results of the acute toxicity test. Perfluorinated compounds （PFCs） inhibited both growth and reproduction of D. magna during the testing period. The ingestion rates and the biomarkers, including ACHE, SOD, and CAT activities, were significantly inhibited by PFCs in most cases. Moreover, the combined effects related to the growth and reproduction showed the antagonistic effects of PFCs.

关键词： Toxicity effect Perfluorononanoic acid Perfluorooctane sulfonate Daphnia magna Reproduction Ingestion rate Biomarker

A meta-analysis of the yield of capsule endoscopy compared to double-balloon enteroscopy in patients with small bowel diseases

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World Journal of Gastroenterology 2007年第32期13卷 4372-4378页

作者： Xiang Chen Zhi-Hua Ran jin-lu Tong Department of gastroenterology Renji Hospital Shanghai Jiao Tong University School of Medicine Shanghai Institute of Digestive Disease Shanghai 200001 China

AIM:To compare the diagnostic yield of capsule endoscopy (CE) with that of double-balloon enteroscopy (DBE). METHODS:Pubmed,Embase,Elsevier ScienceDirect,the China Academic Journals Full-text Database,and Cochrane Controlled Trials Register were searched for the trials comparing the yield of CE with that of DBE. Outcome measure was odds ratio (OR) of the yield. Fixed or random model method was used for data analysis. RESULTS:Eight studies (n = 277) which prospectively compared the yield of CE and DBE were collected. The results of meta-analysis indicated that there was no difference between the yield of CE and DBE 170/277 vs 156/277,OR 1.21 (95% CI:0.64-2.29). Based on sub analysis,the yield of CE was significantly higher than that of double-balloon enteroscopy without combination of oral and anal insertion approaches 137/219 vs 110/219,OR 1.67 (95% CI:1.14-2.44),P 0.05). A focused meta-analysis of the fully published articles concerning obscure GI bleeding was also performed and showed similar results wherein the yield of CE was significantly higher than that of DBE without combination of oral and anal insertion approaches 118/191 vs 96/191,fixed model:OR 1.61 (95% CI:1.07-2.43),P luSION:With combination of oral and anal approaches,the yield of DBE might be at least as high asthat of CE. Decisions made regarding the initial approach should depend on patient's physical status,technology availability,patient's preferences,and potential for therapeutic endoscopy.

关键词： Capsule endoscopy Double balloon enteroscopy Yield Meta-analysis

Isolation and characterization of gasoline-degrading bacteria from gas station leaking-contaminated soils

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Journal of Environmental Sciences 2006年第5期18卷 969-972页

作者： lu Si-jin WANG Hong-qi YAO Zhi-hua College of Water Sciences Beijing Normal University Beijing 100875 China

The effects of culture conditions in vitro and biosurfactant detection were studied on bacterial strains capable of degrading gasoline from contaminated soils near gas station. The main results were summarized as follows. Three bacteria （strains Q10, Q14 and Q18） that were considered as efficiently degrading strains were isolated and identified as Pseudomonas sp., Flavobaeterium sp. and Rhodococcus sp., respectively. The optimal growth conditions of three bacteria including pH, temperature and the concentration of gasoline were similar. The reduction in surface tension was observed with all the three bacteria, indicating the production of biosurfactant compounds. The value of surface tension reduced by the three strains Q10, Q14 and Q18 was 32.6 mN.m, 12.4 mN. m and 21.9 mN.m, respectively. Strain Q10 could be considered as a potential biosurfactant producer. Gasoline, diesel oil, benzene, toluene, ethylbenzene and xylene （BTEX） could easily be degraded by the three isolates. The consortium was more effective than the individual cultures in degrading added gasoline, diesel oil, and BTEX. These results indicate that these strains have great potential for in situ remediation of soils contaminated by gas station leaking.

关键词： gasolene BTEX bacteria biosurfactant consortium

Experimental Investigation on Starting Process of Supersonic Single-stage Air Ejector

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Journal of Thermal Science 2012年第4期21卷 348-353页

作者： Zou Jian-jun Zhou jin lu Hui-qiang Hu Yong College of Aerospace and Material Engineering National University of Defense Technology Changsha 410073 China

This paper deals with experimental study of flow field of starting process in two-dimensional, single-stage supersonic ejector on different air total pressure. Schlieren pictures of flow field were taken, static pressure distribu-tions on side wall were measured. The obtained results show that, on critical pressure, the starting main shock waves in ejector oscillated back and forth between the second throat and the middle section of the mixing chamber, it causes the pressure in the second half of the mixing chamber acutely fluctuated .When the working pressure of the active flow is higher than the critical starting pressure, ejector starts normally and the inner flow-field of the mixing chamber keeps stable and the shock waves in the second throat have a certain degree of oscillation . After ejector starts, the operating pressure of the active flow may be lower than the starting pressure .

关键词： supersonic ejector start process flow-field shock waves

Real-time adaptive particle image velocimetry for accurate unsteady flow field measurements

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Science China(Technological Sciences) 2022年第9期65卷 2143-2155页

作者： OUYANG ZhenXing YANG Hua lu jin HUANG YongAn YIN ZhouPing State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Almost all conventional open-loop particle image velocimetry(PIV) methods employ fixed-interval-time optical imaging technology and the time-consuming cross-correlation-based PIV measurement algorithm to calculate the velocity *** this study,a novel real-time adaptive particle image velocity(RTA-PIV) method is proposed to accurately measure the instantaneous velocity field of an unsteady flow *** the proposed closed-loop RTA-PIV method,a new correlation-filter-based PIV measurement algorithm is introduced to calculate the velocity field in real ***,a Kalman predictor model is established to predict the velocity of the next time instant and a suitable interval time can be *** adaptively adjust the interval time for capturing two particle images,a new high-speed frame-straddling vision system is developed for the proposed RTA-PIV *** fully analyze the performance of the RTA-PIV method,we conducted a series of numerical experiments on ground-truth image pairs and on real-world image sequences.

关键词： real-time adaptive particle image velocimetry flow field measurement high-speed vision correlation filter

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Enhancement of β-Phase Crystal Content of Poly(vinylidene fluoride)Nanofiber Web by Graphene and Electrospinning Parameters

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Chinese Journal of Polymer Science 2020年第11期38卷 1239-1247,I0008页

作者： lu jin Yan Zheng Ze-Kun Liu Jia-Shen Li Yang-Pei-Qi Yi Yang-Yang Fan lu-lu Xu Yi Li Department of Materials School of Natural SciencesThe University of ManchesterManchester Ml 39PLU.K. School of Fashion Zhongyuan University of TechnologyZhengzhou 450007China

Electrospun poly(vinylidene fluoride)(PVDF)nanofiber web has been widely utilized as a functional material in various flexible sensors and generators due to its high piezoelectricity,ease processability,and low *** all the crystalline phases of PVDF,β-phase is a key property for PVDF nano fiber web,because the con tent of β-phase is directly proporti onal to piezoelectric performa nee of PVDF nano fiber ***,the impact of graphe ne con tent(GC),tip-to-collector dista nee(TCD),and rotational speed of collector(RSC),as well as their interactions on theβ-phase formation of PVDF nano fiber web is systematically investigated via design of experime ntal *** fraction of each crystalline phase of PVDF nano fiber web is calculated by FTIR spectra,and the crystallinity is determined by XRD *** influences of GC,TCD,and RSC on both β-phase fraction and crystallinity of PVDF nanofiber are analyzed using Minitab *** results show that GC,TCD,and RSC all have significa nt effect on the β-phase content of PVDF nano fiber web,and GC is the most significant *** addition,an optimal electrospinning condition(GC=1 wt%,TCD=4 cm,and RSC=2000 r·min^-1)to fabricate high 0-phase crystallinity of PVDF nanofiber web is drawn,under which the crystallinity can reach 41.7%.The contributions in this study could provide guidanee for future research on fabricating high performance PVDF nanofiber web based sensors or generators.

关键词： Graphene Electrospinning Poly(vinylidene fluoride) Design of experiment βCrystal phase